Chromatium glycolicum sp. nov., a moderately halophilic purple sulfur bacterium that uses glycolate as substrate

From the microbial mats that develop in Solar Lake, a new purple sulfur bacterium was isolated. This strain (Chromatium strain SL 3201) was morphologically similar to Chromatium gracile and Chromatium minutissimum. Chromatium SL 3201 was found to be a moderate halophile with a growth range between 2 and 20% NaCl (optimum 4-5% NaCl) and was able to grow photo-organotrophically using glycolate and glycerol. It is the first described phototrophic sulfur bacterium able to use glycolate. According to NaCl requirements and utilization of organic compounds, the strain is not related to any known species of the genus Chromatium. On the basis of its 16S rRNA gene sequence, it clusters with other Chromatium species and is most similar to Chromatium salexigens and Chr. gracile, but it is sufficiently separated to be considered as a new species of the genus. It is, therefore, described as Chromatium glycolicum sp. nov.